Growth fitness, virulence, and heat tolerance of Salmonella Typhimurium variants resistant to food preservation methods.
Int J Food Microbiol
; 422: 110810, 2024 Sep 16.
Article
in En
| MEDLINE
| ID: mdl-38945050
ABSTRACT
To study potential ramifications of antimicrobial resistance, we carried out adaptive laboratory evolution assays (ALE) to isolate three resistant variants (RVs) of Salmonella enterica Typhimurium, employing three different types of food preservation methods:
1) an emergent technology, plasma-activated water (PAW), leading to variant RV-PAW; a traditional method, heat, leading to variant RV-HT, and a natural antimicrobial compound, carvacrol, leading to variant RV-CAR. The variant resistant to plasma-activated water, RV-PAW, had mutations in rpoA and rpoD; it showed increased tolerance to heat in orange juice but ultimately did not pose a significant threat, as it exhibited a fitness cost at refrigeration temperature (8 °C), whereas its virulence against Caenorhabditis elegans decreased. The variant resistant to heat, RV-HT, had mutations in flhC, dnaJ it exhibited a fitness cost at high growth temperatures (43 °C) and induced morphofunctional alterations in C. elegans. The variant resistant to carvacrol, RV-CAR, had mutations in sseG, flhA, wbaV, lon; this variant not only exhibited significantly higher thermotolerance in both laboratory media and food models but also effectively increased its growth fitness at refrigeration temperatures while retaining its virulence, evidenced by the highest percentage of Smurf phenotype in C. elegans. To address these challenges, we applied a process combining thermal treatment with citral, with the aim of leveraging the sublethal damage caused in RVs by heat treatments in orange juice. This approach achieves enhanced microbial inactivation without having to escalate the intensity of the thermal treatment. The result was particularly encouraging in the case of RV-CAR, the most challenging strain, for which we improved lethality by up to 3 log10 inactivation cycles.Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Salmonella typhimurium
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Caenorhabditis elegans
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Food Preservation
/
Hot Temperature
Limits:
Animals
Language:
En
Journal:
Int J Food Microbiol
Journal subject:
CIENCIAS DA NUTRICAO
/
MICROBIOLOGIA
Year:
2024
Document type:
Article
Affiliation country:
Country of publication: